#!/bin/bash
 
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# @@@ END COPYRIGHT @@@


# -----------------------------------------------------------------------------
# script: krb5service
#
# This script manages the Kerberos ticket service for Trafodion 
#
# The Kerberos ticket service consists of three scripts:
#    - krb5service (this script) which manages the service
#    - krb5check - wakes up periodically to log ticket status and renew tickets
#    - krb5functions - contains common functions used by krb5service & krb5check
#
# (krb5check runs in an infinite loop which wakes up periodically to check to
#  see if the Trafodion ticket is ready to expire. If ticket is ready to expire, 
#  it renews the existing ticket if retries are available. If no more retries 
#  are available, it reports the problem and continues. Ticket life times and 
#  renewal life times are based on the ticket defaults. The script periodically 
#  reports the ticket status to a log file.)
#
# Options:
#   init    - inits a new Trafodion ticket based on existing ticket attributes 
#   restart - stops then restarts the ticket renewal service
#   start   - starts the ticket renewal service
#   status  - displays the status of the Trafodion service ticket
#   stop    - stops the ticket renewal service
#
# Location attributes (see krb5functions to change these values):
#  [LOG_FILE]  : $TRAF_LOG/krb5check - log where all events are stored
#    (the log file is recreated each time the krb5service is started)
#  [LOCK_FILE] : $TRAF_VAR/krb5check - file to keep track of krb5check process
#    (acts as a semiphore to prevent multiple occurrances from running)
#  [CACHE_FILE]: /tmp/krb5cc_(trafodion linux UID) - default location for Kerberos
#    cache ticket store (CACHE_FILE)
#  [KEYTAB]: /etc/security/keytabs/trafodion.service.keytab - location where trafodion keytab reside
#
# This script makes a call to krb5check and accepts the following parameters: 
#   (changes are required if different defaults are needed) 
#  -c <cache location> location of Kerberos cache, 
#     (defaults to /tmp/krb5cc_uid)
#  -w <wnum> time (in seconds) to wait before checking ticket expiration, 
#     (defaults to 5 minutes)
#  -r <rnum> when to display ticket status to the log file, 
#     (defaults to 12 times which is 60  minutes ( <wnum> * <rnum>)
# ------------------------------------------------------------------------------

source krb5functions

# =================================================
# msg:
#    write a message the log
# =================================================
function msg
{
  echo "krb5service[$$] `date`: $1"
  echo "krb5service[$$] `date`: $1" >> $LOG_FILE
}

# =================================================
# Main
# =================================================
LOCK_FILE=""
getLockFile
LOG_FILE=""
getLogFile
CACHE_FILE=""
KEYTAB=""
getKeytab

currentPID="NC"
if [ -f $LOCK_FILE ]; then
  PID=$( cat $LOCK_FILE )
fi

# if LOCK_FILE contains digits, then good PID exists
if [[ $PID = *[[:digit:]]* ]]; then
  currentPID=`ps -p $PID | grep krb5check | awk '{print $1}'`
fi

# if the current kbr5check PID matches what is stored in LOCK_FILE
# then we have an active process
serviceRunning=0
if [[ $currentPID = *[[:digit:]]* ]]; then
  if [ "$currentPID" == "$PID" ]; then
    serviceRunning=1
  fi
fi

# =========================================================================
# parse the request
doInit=0
doStart=0
doStatus=0
doStop=0

TICKET_STATUS=""

case "$1" in
    init)
        doInit=1
        ;;
    restart)
        doStop=1
        doStart=1
        ;;
    start)
        doStart=1
        ;;
    status)
        doStatus=1
        ;;
    stop)
        doStop=1
        ;;
    *)
        echo $"Usage: $0 {init | restart | start | status | stop}"
        exit 1
        ;;
esac

# =========================================================================
# Perform the <init> request
if [ $doInit -eq 1 ]; then
  msg "service init requested"

  # get keytab
  msg "using keytab: $KEYTAB"

  # get principal
  #   if cached ticket exists, extract principal from cached location
  #   else ask kerberos for a list of principals based on the keytab, assume
  #     only one entry is returned (??)
  HOST_NAME=`hostname -f`
  getCachedTicket
  if [[ $? -eq 0 ]]; then
    PRINCIPAL="$( klist -c $CACHE_FILE | grep 'Default principal' | awk '{print $3}' )"
  else
    PRINCIPAL=`klist -kt $KEYTAB | grep $HOST_NAME | awk '{print $4}' | uniq`
  fi
    
  valid=`echo $PRINCIPAL | grep "$HOST_NAME" | wc -l`
  if [[ $valid -eq 0 ]]; then
    msg "Could not find valid principal ($PRINCIPAL)"
    exit 1
  fi 
  msg "using principal: $PRINCIPAL"

  kinit -k -t $KEYTAB $PRINCIPAL
  if [ $? -ne 0 ]; then
    msg "An error occurred while initializing $PRINCIPAL"
    exit 1
  else
    msg "Initialized ticket for principal $PRINCIPAL"
    msg "`klist`"
  fi
  exit 0
fi

# =========================================================================
# Perform the <status> request
#
#  returns:
#    0 - valid ticket
#    1 - no ticket
#    2 - expired or ready to expire ticket

if [ $doStatus -eq 1 ]; then
  if [ $serviceRunning -eq 0 ]; then
    echo "service not running"
  fi
  getCachedTicket
  if [[ $? -eq 0 ]]; then
    getStatus
    retcode=$?
    echo $TICKET_STATUS
  else
    echo "Ticket information not found"
    retcode=1
  fi
  exit $retcode
fi


# =========================================================================
# Perform the <stop> request
if [ $doStop -eq 1 ]; then
  msg "service stop requested"
  if [ $serviceRunning -eq 1 ]; then
    msg "service is running"
    kill -9 $currentPID
    rm $LOCK_FILE
    msg "service stopped for $currentPID"
  fi
fi

# =========================================================================
# Perform the <start> request
if [ $doStart -eq 1 ]; then
  msg "service start requested"

  # If the lockfile already exists then another process must be running
  if [ -f $LOCK_FILE ]; then
    if [ $serviceRunning -eq 1 ]; then
      msg "service already running with pid $( cat $LOCK_FILE )"
      exit 1
    fi
  fi

  # remove log, may want to handle log garbage collection differently 
  rm $TRAF_LOG/krb5check 

  # kick off a process that wakes up once in a while and check for 
  # ticket expirations

  getCachedTicket
  if [[ $? -eq 1 ]]; then
    msg "ERROR: Ticket is not available"
  fi
  getStatus
  msg "starting service (krb5check)"
  msg "$TICKET_STATUS"
  $TRAF_HOME/sql/scripts/krb5check -r 2 -w 300 &
  krb5checkPID=`echo $!`

  # see if process started successfully
  sleep 5
  existingPID=`ps -p $krb5checkPID | grep krb5check | awk '{print $1}'`
  if [ ! "$existingPID" == "$krb5checkPID" ]; then
    msg "service (krb5check) did not start, check $LOG_FILE for details" 
  fi
fi

# =========================================================================
exit 0
